Decimal alignment in a table with math mode

Question

After reading some answers on the site, I'm trying to use dcolumn pacakge in order to add horizontal alignment to my tables. Unfortunately without success so far. I'm writing as a part of a group so I shouldn't added packages that may affect others, that's why I'm trying to figure it w/o adding the siunitx package.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{booktabs}
\usepackage{multirow}
\usepackage{ctable}
\usepackage{tabularx}
\usepackage{graphicx}
\usepackage{dcolumn} 
\newcolumntype{d}[1]{D{.}{.}{#1} }


\begin{document}

\begin{table}[]
    \centering
    \begin{tabular}{@{}lc*{4}{d{1.5}}@{}}
        \toprule
        {} & {} & \multicolumn{2}{c}{Group A} & \multicolumn{2}{c}{Group B} \\
        \cmidrule(lr){3-4}  \cmidrule(l){5-6}
        Types & Character & Results A & Results B     & Results A & Results B     \\
        \midrule
        \multirow{3}{*}{Main}
        {}    & The Good & .111      & .789_{b}^{b}  & .520      & .555_{b}^{a}  \\
        {}    & The Bad  & .111      & .636_{b}^{al} & .520      & .730_{b}^{al} \\
        {}    & The Ugly & .111      & .525_{b}      & .520      & .696_{b}      \\
        \bottomrule
    \end{tabular}
    \caption{Caption}
    \label{tab:my_label}
\end{table}

The result is:

Please help me solve this puzzle, also I need to add bold to some values in the table, and since switching to dcolumn I've removed the $n$ I've had and therefore \mathbf seems not to work any more. What would be the solution in that case?

Answer 1

You are probably looking for \multicolumn:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{booktabs}
\usepackage{multirow}
\usepackage{ctable}
\usepackage{tabularx}
\usepackage{graphicx}
\usepackage{dcolumn}
\newcolumntype{d}[1]{D{.}{.}{#1} }


\begin{document}

\begin{table}[]
  \centering
  \begin{tabular}{@{}lc*{4}{d{1.5}}@{}}
    \toprule
    {} & {} & \multicolumn{2}{c}{Group A} & \multicolumn{2}{c}{Group B} \\
    \cmidrule(lr){3-4}  \cmidrule(l){5-6}
    Types & Character & \multicolumn{1}{c}{Results A} & \multicolumn{1}{c}{Results B} & \multicolumn{1}{c}{Results A} & \multicolumn{1}{c}{Results B}  \\
    \midrule
    \multirow{3}{*}{Main}
    {}    & The Good & .111      & .789_{b}^{b}  & .520      & .555_{b}^{a}  \\
    {}    & The Bad  & .111      & .636_{b}^{al} & .520      & .730_{b}^{al} \\
    {}    & The Ugly & .111      & .525_{b}      & .520      & .696_{b}      \\
    \bottomrule
  \end{tabular}
  \caption{Caption}
  \label{tab:my_label}
\end{table}

\end{document}

However, as mentioned in the comments, I think you should reconsider the case against siunitx. More important than being a "basic package" is the fact that it is very well crafted and zealously maintained, besides being widely used. (This is not a judgement on dcolumn of which I'm not an user). You should, of course, decide that along with your work group.

The same table done with siunitx would be something like:

\documentclass{article}

\usepackage{booktabs}
\usepackage{multirow}
\usepackage{siunitx}

\begin{document}

\begin{table}
  \centering
  \sisetup{table-format = 0.3}
  \begin{tabular}{@{}
    lc
    S
    S[table-space-text-post = {$_{b}^{al}$}] % make it the largest post-number element
    S
    S[table-space-text-post = {$_{b}^{al}$}]
    @{}}
    \toprule
          &           & \multicolumn{2}{c}{Group A}     & \multicolumn{2}{c}{Group B}    \\
    \cmidrule(lr){3-4}  \cmidrule(l){5-6}
    Types & Character & {Results A} & {Results B}       & {Results A} & {Results B}      \\
    \midrule
    \multirow{3}{*}{Main}
          & The Good  & .111        & .789{$_{b}^{b}$}  & .520        & .555{$_{b}^{a}$}  \\
          & The Bad   & .111        & .636{$_{b}^{al}$} & .520        & .730{$_{b}^{al}$} \\
          & The Ugly  & .111        & .525{$_{b}$}      & .520        & .696{$_{b}$}      \\
    \bottomrule
  \end{tabular}
  \caption{Caption}
  \label{tab:my_label}
\end{table}

\end{document}

It does automatically take care of the leading zero, emphasized by @Denis in the comments.

Answer 2

You can (should, in my opinion) use siunitx; here I show also how to have real note markers upright that leave the exact space for them.

If you want to set some of the entries bold, there is a trick adapted from https://tex.stackexchange.com/a/352028/4427

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{booktabs}
\usepackage{siunitx}

\NewDocumentCommand{\bs}{}{\fontseries{b}\selectfont}

\makeatletter
\NewDocumentCommand{\tss}{mm}{%
  {\m@th\ensuremath{%
    ^{\mbox{\fontsize\sf@size\z@\selectfont #1}}%
    _{\mbox{\fontsize\sf@size\z@\selectfont #2}}%
  }}%
}
\makeatother

\begin{document}

\begin{table}[htp]
\centering

\sisetup{detect-weight,mode=text}
\DeclareDocumentCommand{\bfseries}{}{\bs}

\begin{tabular}{
  @{}
  l
  c
  S[table-format=1.3]
  S[table-format=1.3,table-space-text-post=\tss{al}{b}]
  S[table-format=1.3]
  S[table-format=1.3,table-space-text-post=\tss{al}{b}]
  @{}
}
\toprule
 & & \multicolumn{2}{c}{Group A} & \multicolumn{2}{c}{Group B} \\
\cmidrule(lr){3-4}  \cmidrule(l){5-6}
Types & Character & {Results A} & {Results B} & {Results A} & {Results B} \\
\midrule
Main & The Good & \bs .111 & .789\tss{b}{b}  & .520 & .555\tss{a}{b}  \\
     & The Bad  &     .111 & .636\tss{al}{b} & .520 & .730\tss{al}{b} \\
     & The Ugly &     .111 & .525\tss{}{b}   & .520 & .696\tss{}{b}   \\
\bottomrule
\end{tabular}

\caption{Caption}
\label{tab:my_label}

\end{table}

\end{document}

I wouldn't use \multirow: blank space below “Main” means repetition. Shifting it down makes quite unclear whether “Main” refers to all rows or just the middle one.